Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1
Could you please send a few links you can't download. We will check it out.
Do you download via the extension SaveFrom.net Helper or the website SaveFrom.net?
For the better understanding it'll be great to see a screenshot with the error.

Hello, this extension has been fixed. Please, update or reinstall it from our site.
The latest version is 8.29: http://en.savefrom.net/user.php#helper_install
Thank you for using Savefrom.Net browser extension

This extension has been fixed. Please, update or reinstall it from our site.
The latest version is 8.29: http://en.savefrom.net/user.php#helper_install
Thank you for using Savefrom.Net browser extension

This bug is known to us, we will try to fix in the nearby future.

Hi. We'll try to fix it ASAP.

Hello, thank you for contacting support in Savefrom.Net
This bug is known to us, we will try to fix in the nearby future.

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1

Hello, we’d like to help you, but we will need some info about your browser and the installed extension first.
Please, go here http://en.savefrom.net/user.php?info=1
Copy the details that you see and send them back to us.
Please also send us some video links that you can’t download.
Thank you for contacting Savefrom.Net support !

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1

For the better understanding it'll be great to see a screenshot with the error.

Hello, please, send us more details regarding the problem.